In cigarette packaging machines, it is known to use a wheel for forming cigarette groups, each arranged to constitute the contents of one packet. For this purpose, said forming wheel comprises a plurality of axial containers which, during the rotation of said wheel, pass through a loading station comprising an outlet of a cigarette feed hopper, and receive from this latter several successive superposed layers of cigarettes.
In particular, in the most common case, said hopper comprises three separate outlet mouths, each of which is divided into a plurality of channels of number equal to the number of component cigarettes in the individual layers.
Normally, said loading station also comprises pusher elements which act axially on the cigarettes disposed mutually adjacent at the lower end of the individual mouths, to push them into said axial containers as these latter pass in front of said mouths.
One of the main problems which arise during the formation of groups of cigarettes by means of the successive superposing of layers consists of the fact that these latter, as they are superposed one of another, must be kept in position radially relative to said forming wheel.
At present, there are two main methods used for retaining the layers of cigarettes in a radial direction.
The first of the aforesaid methods, described for example in USA Pat. No. 2,334,142 and in British Patent No. 2,048,837, consists of disposing in each container fixed separation baffles wich divide the container into several superposed compartments each arranged to receive one layer of cigarettes.
The second of said methods, described in USA Pat. No. 3,603,445, consists of disposing in each container elastic elements arranged to act transversely on the cigarettes in a direction parallel to each of said layers.
Both the aforesaid methods have drawbacks when applied to extremely fast packaging machines, i.e. packaging machines in which the rotational speed of the forming wheel is extremely high, and in which the rate of insertion of the layers of cigarettes into the relative containers is likewise high.
In this respect, transversely locking the layers of cigarettes by the aforesaid elastic elements or the like is insufficient to retain the layers in position when the centrifugal force applied to the cigarettes exceeds a certain limit. On the other hand, the presence of baffles in the containers automatically limits the rate of introduction of the cigarettes, which in order not to collide with said baffles must, before being introduced into the relative containers, pass through a sort of die which radially compresses them, causing tearing of the paper if the passage speed exceeds a certain limiting value.